diff --git a/ui-ngx/src/app/shared/models/time/time.models.ts b/ui-ngx/src/app/shared/models/time/time.models.ts
index acb62d9d2a..c204cb6867 100644
--- a/ui-ngx/src/app/shared/models/time/time.models.ts
+++ b/ui-ngx/src/app/shared/models/time/time.models.ts
@@ -431,7 +431,7 @@ export const initModelFromDefaultTimewindow = (value: Timewindow, quickIntervalO
       if (isDefined(value.history.quickInterval)) {
         model.history.quickInterval = value.history.quickInterval;
       }
-      if (isDefined(value.history.fixedTimewindow)) {
+      if (isDefinedAndNotNull(value.history.fixedTimewindow)) {
         if (isDefined(value.history.fixedTimewindow.startTimeMs)) {
           model.history.fixedTimewindow.startTimeMs = value.history.fixedTimewindow.startTimeMs;
         }